| 摘要 |
PROBLEM TO BE SOLVED: To reduce the influence of the deviation of a mask at the time of forming an offset drain region in a MOS field effect transistor having a high breakdown voltage and, in addition, to optimize the trade-off between the breakdown voltage and on-resistance of the transistor. SOLUTION: The concentration of electric fields to the part of the n-type offset drain region 32 protruded to a source side than a field oxide film 33 is relaxed by making the quantity of impurities per unit area in the protruded part smaller than that of impurities per unit area in the part of the region 32 under the field oxide film 33 by forming the protruded part to have a comb- shaped flat surface. COPYRIGHT: (C)2003,JPO
|
